The industry has had a long felt need for a thermosetting resin that is capable of imparting a highly useful combination of high dry tensile strength and high temporary wet strength to a paper product.
U.S. Pat. No. 3,556,932, for instance, discloses a composition that imparts high dry tensile strength to paper. Unfortunately, it has been discovered that the resin loses approximately only 50% of its wet tensile when soaked in water for 30 minutes. Paper manufacturers and consumers would prefer to have a resin that loses more during such a period of time. U.S. Pat. No. 4,605,702 discloses a composition that imparts high temporary wet strength properties to paper such that 60 to 80% of the wet tensile is lost when soaked in water for 30 minutes.
It would be highly useful to develop a resin, which when applied to paper, has a temporary wet tensile properties of the same order of magnitude as U.S. Pat. No. 4,605,702 but a dry tensile strength intermediate to both U.S. Pat. No. 3,556,932 and U.S. Pat. No. 4,605,702.
For the foregoing reasons, there is a need to develop an improved thermosetting strength resin.